The broad concept of a device that can function as a calculator and a musical device is known. For example, U.S. Pat. No. 4,352,313 shows a piano-type keyboard fastened to a standard alpha-numeric computer keyboard. The keys on the piano-type keyboard are in contact with the keys on the computer keyboard to generate musical notes. When a user depresses a key on the piano-type keyboard, a key on the computer keyboard is also depressed, and a musical note is produced.
Another known device with calculating and music generating capabilities is a typical hand-held calculator having numerical keys which are also designed to generate a limited selection of musical notes. However, such a device has small and tightly-spaced keys on the keyboard. Thus, it is difficult to play the keyboard by "touch". It is also difficult to play notes at any speed without accidentally hitting unwanted notes. Moreover, when such a device is laid on a support surface, the keyboard would be disposed in a generally horizontal orientation a short distance about the support surface. Such an orientation would be uncomfortable to play for any appreciable period of time.
Applicant believes that a combined calculating and musical device with a keyboard which simulates the keyboard of a desk-top electronic ten-key calculator has advantages over the foregoing types of devices. Specifically, a desk top electronic calculator, when resting on a surface such as a desk top, has a keyboard housing which is spaced from and angled upwardly relative to the surface upon which the calculator rests. The geometry of the keyboard, and the arrangement of numerical and function keys thereon, are designed to allow a user to comfortably and rapidly enter data and commands over long periods of time by "touch" (rather than "hunt-and-peck") techniques For example, the contact surfaces of the keys are spaced far enough apart to correspond with the natural, relaxed spacing of a user's fingers, thereby minimizing strain on the fingers and the risk that more than one key may be inadvertently hit at one time. Moreover, when the device is resting on a surface, the angled keyboard permits a user to rest a forearm on the surface while actuating the keys, thereby enabling the user to comfortably actuate the keys over long periods of time. Such features facilitate rapid entry of data or commands into the calculator, over long periods of time.
Applicant believes the foregoing features of a desk, top electronic calculator keyboard make it particularly suited for use as a music generating device. For example, the design of the keyboard permits a user comfortably to enter key strokes over significant periods of time without becoming tired or cramped. Also, the spacing of the keys is such that a user can comfortably and selectively actuate single or multiple keys. Additionally, for those who are or become skilled at operating a desk-top electronic calculator keys by "touch", a musical score written in terms of the layout of the keys of an electronic calculator keyboard enables music to be played almost instantaneously, by "touch", rather than hunt-and-peck techniques.
In contrast, a typical hand-held calculator, while having one advantage over the desk-top calculator in that it is small and portable, has the disadvantage in that it is generally not as comfortable or as easy to enter keystrokes on the keyboard. The typical hand-held calculator has keys that are usually small and tightly-spaced, and a keyboard that is not angled from the support surface. For example, a typical hand-held calculator has key contact surfaces that are spaced less than 3/16" apart. When the calculator is resting on a surface, the keyboard is angled at less than five degrees with respect to the surface. On the other hand, the desk-top electronic ten-key calculator has key contact surfaces that are spaced at least 1/4" apart and has an angle of at least eight degrees with respect to the support surface. The key spacing and angle of the keyboard permit a more comfortable and efficient actuation of the keys than with a typical hand-held calculator. Consequently, the inputting of keystrokes on a desk-top electronic calculator can be a relatively quick and easy process compared to the inputting of keystrokes on a hand-held calculator.